Waist-to-Height Ratio Detects Fat Obesity in Children and Adolescents Significantly Better than BMI

The following is excerpted from an online article posted by ScienceDaily.

An inexpensive measure of obesity in children and adolescents that could replace body mass index (BMI) has been identified in a new study as waist circumference-to-height ratio. This measure detected excess fat mass and distinguished fat mass from muscle mass in children and adolescents more accurately than BMI.

The study was conducted in collaboration between the University of Bristol in the UK, the University of Exeter in the UK, and the University of Eastern Finland, and the results were published in Pediatric Research.

For nearly a generation, weight-to-height ratio charts and BMI for age and sex have been used to diagnose children with obesity. However, these surrogate assessment tools are inaccurate in childhood and adolescence since they do not distinguish fat mass from muscle mass. For instance, two children with similar BMI might have different proportions of fat and muscle mass which makes obesity diagnosis difficult.

Expensive tools such as the dual-energy Xray absorptiometry (DEXA) scan accurately measures fat and muscle content of the body, but this device is not readily available in primary health care centers. Recently, the American Academy of Pediatrics (AAP) published a clinical guideline on childhood obesity and requested urgent research on inexpensive and accurate alternative measures of obesity.

There has been no former evaluation of how much waist circumference-to-height ratio measurements agree with DEXA-measured fat mass and muscle mass during growth from childhood to young adulthood. In addition, the threshold of waist circumference-to-height ratio needed to detect excess fat in children is not clear, hence this new  study.

The study included 7,237 children (51% females) aged 9 years who were followed-up until age 24 years. Their BMI and waist circumference-to-height ratio were measured at ages 9, 11, 15, 17, and 24 years.

Waist circumference-to-height ratio had a very high agreement of 81 -- 89% with DEXA-measured total body fat mass and trunk fat mass, but a low agreement with muscle mass (24 -- 39%). BMI had a moderate agreement with total fat mass and trunk fat mass (65 -- 72%) and muscle mass (52 -- 58%).

The study concluded that waist circumference-to-height ratio might be preferable to BMI assessment in children and adolescent clinics as an inexpensive tool for detecting excess fat. Parents should not be discouraged by the BMI or weight of their children but can inexpensively confirm whether the weight is due to increase in excess fat by examining their kid's waist circumference-to-height ratio.

Source: ScienceDaily
https://www.sciencedaily.com/releases/2024/03/240305134243.htm